Vermont reports 1st human West Nile virus case of 2017

Vermont health officials have confirmed the year’s first case of human illness due to West Nile virus. An Addison County resident was diagnosed earlier this month with neuroinvasive disease – a more serious form of the illness which affects the nervous system.

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Since 2003, there have been 12 confirmed human cases of West Nile virus in Vermont. Two Windsor County residents were diagnosed with West Nile neuroinvasive disease in 2016 (HERE and HERE).

Health officials said the risk of illness is highest in late summer and early fall, continuing until the first hard frost, and are encouraging Vermonters to take precautions to avoid mosquito bites.

“Our surveillance has found mosquitoes infected with West Nile virus in all parts of the state,” said Bradley Tompkins, infectious disease epidemiologist with the Vermont Department of Health. “Mosquito-borne diseases can be serious and sometimes fatal. It’s important for people to protect themselves from bites.”

West Nile virus is spread through the bite of an infected mosquito. The virus has been found in all counties of Vermont and continues to be detected in mosquitoes each year. Most people who are infected do not become ill, but around 20 percent develop flu-like symptoms such as high fever, muscle aches, headache and fatigue. Fewer than 1 percent develop the more severe illness.

As of September 19, 2017, a total of 47 states and the District of Columbia have reported West Nile virus infections in people, birds, or mosquitoes in 2017. Overall, 875 cases of West Nile virus disease in people have been reported to CDC. Of these, 537 (61%) were classified as neuroinvasive disease (such as meningitis or encephalitis) and 338 (39%) were classified as non-neuroinvasive disease.